


Heart of Darkness

by DarthImperiusArchive (DarthImperius)



Category: Harry Potter - J. K. Rowling, Kingdom Hearts
Genre: Alternate Timelines, Alternate Universe, Alternate Universe - Canon Divergence, Crossover, Gen, Kingdom Hearts 358/2 Days - Freeform, Organization XIII - Freeform, Wrong Boy-Who-Lived (Harry Potter)
Language: English
Status: In-Progress
Published: 2019-02-27
Updated: 2019-04-11
Packaged: 2019-11-06 17:16:46
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,437
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17943872
Author URL: https://archiveofourown.org/users/DarthImperius/pseuds/DarthImperiusArchive
Summary: Amidst the rising darkness, the Keyblade is bequeathed to yet another wielder. But even though the Keyblade's light is enough to strike down the Heartless, their lingering threat is enough to drive away Harry Potter from his home and family, believing his presence a danger to them.





	1. Farewell

**Author's Note:**

  * Inspired by [Sacred Moon](https://archiveofourown.org/works/3312905) by [DarthImperiusArchive (DarthImperius)](https://archiveofourown.org/users/DarthImperius/pseuds/DarthImperiusArchive). 



> Disclaimer: Harry Potter belongs to J.K. Rowling and Kingdom Hearts belongs to Disney and Square Enix.

**_Chapter 1 – Farewell_ **

In your hand, take this key. So long as you have the makings, then through this simple act of taking, its wielder you shall one day be. No ocean will contain you then. No more borders around, or below, or above, so long as you champion the ones you love.

Although he had been very young back then, Harry remembered his grandfather’s words very well. The words that sealed his fate as one of the Keyblade’s chosen. Ever since that day, his grandfather had taught him about the Keyblade and the wielders of such a weapon. First the basic things, stuff that a six-year-old could understand. In that magical place Merlin had created at the request of his grandfather, time held no meaning. He could hardly tell how long it was that they had been there, but he knew it was a long time. And it was there that he had been trained for quite a long time as a Keyblade wielder.

But now he was gone. His grandfather was gone, and his training had stopped. He could be ten years old, but Harry knew that the Keyblade was a beacon for the Heartless since they had begun to invade the Realm of Light a few years ago.

Things had become far more dangerous than they were supposed to be. But, then again, it was his grandfather who did all the-

“Hey there, squibby!”

Whatever thoughts he had were suddenly dispelled, as Harry’s body became stiff and his eyes narrowed slightly in annoyance. Sighing, he relaxed and quickly turned around to look at the newcomer.

Michael.

Why did he have to be so irritating? Never there was a day that he was free from his older brother’s teasing.

The eldest of the Potter children was leaning against the door frame with a smirk on his face.

He had no visible signs of accidental magic. Events of accidental magic were already rare for all wizards, and since those he had happened while with his grandfather, it only made sense that no one else had seen it happen. And for that reason, he had been “branded” by Michael as a squib. He wasn’t really sure if the older of his brothers truly meant those words, of if it was just empty teasing. Regardless, wizard or no, he would not be using a wand in the foreseeable future.

He had a good reason for that. One they could not know.

“What do you want?”

“Oh? Can’t I come and say goodbye to my favourite brother?”

Harry blinked, his face reflecting the confusion which now addled his mind. “Goodbye?”

“Yeah. Hogwarts, remember?” said Michael, slightly waving his wand as if trying to make a point.

“Already?” asked Harry, a bit surprised that it was already the first of September. Time really flew fast.

“Damn Harry! Is your head in another world or something?” asked Michael, amusement and bewilderment evident in his voice. “That’s all we talked about last dinner!”

Did they? Harry could hardly remember, truth be told. He had so much things on his mind that almost all background conversations simply weren’t there at all. Even now, he was half distracted, enough that he had not realized his brother was now sitting right next to him on his bed.

“Still thinking about it?”

Harry knew what was the “it” his brother referred to. It had been nearly three weeks since old Fleamont Potter had died, and while there was the usual sadness when a close family member passed away, things seemed to return to normal as the days passed. Yet of Fleamont’s four grandchildren, Harry had been undoubtedly the closest to him, and this was something all of them knew. He still hadn’t adapted to the fact his grandfather was gone, and sometimes his mind tricked him, making him briefly believe he had not died. Of course, it would take seconds for the reality to crash down hard, leaving Harry with an emptiness in his heart that could not be filled. Not to mention he was often too distracted by thoughts regarding his future. More specifically, what he had been planning to do for a few days.

He nodded in response, but before his brother could say anything else, a voice came from downstairs.

“Michael, hurry!”

It had been their mother who shouted, making the older of the Potter children groan. “Yes mum!”

He ruffled Harry’s hair, drawing a yelp from his younger brother.

“Well, see you in a year, squib!”

Harry watched as his brother ran off, the sound of his footsteps quickly fading away.

And despite everything, Harry could not help but smile.

“May your heart be your guiding key.”

* * *

 

A week had passed since then, and now Harry was at finally prepared for what would come.

Well… “prepared”. That was a lie if ever thought of one. Against what he wanted, he was forcing himself to do this.

Harry looked behind him, the shape of his house and the lights coming from inside vanishing behind the tall trees. In his hand he carried a bag filled with the essentials he would need for the future. The Black Coat he wore would shield him from the darkness in the pathways he would use, but it would also made him extremely hard to see in the darkness that permeated the woods. Unfortunately, this darkness also worked both ways, for he could hardly see anything in the dark of the night.

And yet, the dark itself took shape before him, and Harry saw a dark figure appear before him, the only discernible thing being the dark ragged robes and hood that covered the stranger.

Barely, perhaps, but he could still see the man.

“Leaving them, are you?” he spoke. “Aren’t you acting rashly?”

The voice was deep, but it held a strange familiarity to it, which Harry was unable to pinpoint.

“Who are you?” he demanded.

There was silence. Harry’s hand was twitching, as if eager to summon the Keyblade so that he could drive away whoever this was.

“My name… has no importance,” claimed the unknown man. “But I know yours, Harry Potter… chosen of the Keyblade.”

Harry felt his pulse start to race. That this man knew not just his identity but also the fact that he wielded the Keyblade was alarming. He had never told anyone, and as far as he knew, his grandfather had never told anyone else in this world.

“Tell me, are you truly willing to go ahead with this… adventure of yours?” asked the figure as it approached. “Where exactly will you go? Into light… or into darkness?”

The fact that he was being approached by the stranger made Harry immediately summon his Keyblade, pointing it at the cloaked figure.

“None of your business!” he nearly growled.

The cloaked figure made a sound which Harry could hardly discern, almost like a suppressed laugh or cough.

“In that case…”

Around him dark shapes emerged, the sound of helmet pieces moving invading the near silent forest. Harry knew what these creatures were, but he had never seen this type.

“… allow me to show you.”

Before him, the very air around the cloaked figure shimmered, and the strange man faded away, leaving Harry alone with the small group of Heartless. He immediately dropped the bag, readying himself for battle against the dark creatures. The small Heartless tried to get closer, but Harry simply slashed at them with the Keyblade. It took a few hits for each, but he managed to destroy the Heartless and leave the tense situation unscathed. But the unknown man was gone, and now he was alone in the dark woods. Harry cared little if he came back, but the fact that he had somehow controlled the Heartless made him worried. He knew that the Realm of Light was in danger from a Heartless invasion, and having around someone who could control the Heartless wasn’t good. The Keyhole of this world had been already sealed by his grandfather, so there any attempts at taking its heart would be in vain.

An invasion of the Heartless in this world would end in disaster. For a Keyblade wielder, they were fair game, but normal weapons could not harm the Heartless. And Harry wasn’t sure if the magic of this world could either. He had never seen it, and he wasn’t going to risk it. Not to mention the Keyblade itself served as a beacon for the dark creatures, which meant they would specifically search for him.

It just wasn’t safe for him to remain around. For their sake, he had to leave.

* * *

 

As he left the Corridor of Darkness, Harry’s eyes were met with an orange sky.

Twilight Town.

He had been here once before. He knew little about the town, other than it was in the Realm Between, where few worlds lingered.

Right now, he was in a small clearing, behind him a path that led into the deep forest outside of the city. But his destination was not the city proper, but what lay in its outskirts. Looking at the mansion behind him, Harry saw a few things that caught his attention. More specifically, the broken windows.

He stepped closer to the gate, dropping the bag near it before looking at the chains and lock on the metallic barrier. Eyes drawn to the door behind the gates, Harry smiled.

“Perfect.”

* * *

 

_**Author's Note:** _

Here’s another conceptual plot-bunny, this time somewhat based on “Sacred Moon”, one of my old and abandoned stories. Just to warn you, at the moment there are no foreseeable pairings in the drawing board, so don’t really expect anything of the sort.


	2. The First Worlds

**_ Chapter 2 – The First Worlds _ **

Harry walked around the mansion’s foyer, observing the damage. It was mostly empty, but quite a few decorations remained. This place needed a little work to be habitable again, and if there was something he had, it was time. There was no way he would be going around manually repairing stuff. He had no skills in that field. Thankfully, since the Keyblade could also function as a wand, spells from his world would work here as well. He had learned quite a few during his training sessions, and perhaps it was time to put them to good use. With no Ministry here, the Trace wouldn’t be able to detect any magic he did outside of his homeworld.

Summoning the Keyblade, Harry pointed the weapon at a broken bust.

“Reparo!”

Such a simple yet extraordinarily useful spell, the Mending Charm. Perhaps amongst the most used household spells in the Wizarding World, and if the other rooms were like this, then this mansion would soon become well acquainted with the spell. In instants, the marble bust was as good as new – the mark of a successful spell.

* * *

Harry’s first days in the mansion were… busy. Thanks to the Munny his grandfather had left him, he had little trouble with buying groceries for himself, and cooking food was mostly easy. He could remember most lessons he had been taught by old Fleamont.

And then there were also the Heartless that occasionally appeared outside of the manor. Its position in Twilight Town’s outskirts was rather useful, since it placed the citizens outside of the Heartless’s general path. They wanted him, after all – the wielder of the Keyblade. This day was no different from the others. Do stuff, then destroy Heartless. Afterwards, repeat. It was getting a bit boring, to be honest, and Harry was already having ideas of visiting other worlds, just to get away from this new schedule of his.

Yet unbeknownst to the young wielder of the Keyblade, two figures cloaked in black, hidden amongst the trees of the woods, observed him silently.

* * *

_Heartless. Heartless again._

_It seems my presence here attracts the creatures to this area of Twilight Town. Good enough for me. Less people in both our ways. They’re mostly a nuisance at this point, although thankfully they don’t mess with my repairs._

_Still, I feel alone here. Four days and I already miss everyone. Mum, dad, Matthew, Cyril. Even Michael. I wonder if they already know. Matthew must know since he’s at home, but since Michael and Cyril are at Hogwarts, mum and dad may have not told them yet._

_I keep reminding myself that I can’t be weak. That what I’m doing is for their sake. I just hope the pressure doesn’t break me._

\- Harry’s Report 2

* * *

“So… a hero of the Keyblade in Twilight Town. That’s unexpected.”

Atop the World that Never Was floated the headquarters of the Organization – the Castle that Never War. Within it, the twelve members of the elusive group were inside Where Nothing Gathers, each sitting in their respective throne.

“But why is he there? Should not the master of the Keyblade be battling against the Heartless threat?” wondered Vexen.

“He is avoiding the true battlefield,” suggested Zexion. “The worlds he visits are in the periphery of the Heartless invasion.”

Larxene, the last of the Organization to be inducted into the group, snorted. “Have you seen him? He’s a boy! I’m willing to bet his voice hasn’t even cracked yet!”

Xigbar snorted. “Don’t underestimate the power of a Keyblade wielder, nymph. Very bad idea. You should have seen how he dispatched those Heartless.”

“Gentlemen.”

The discussion had stopped, and all turned to look at the one who sat on the tallest throne.

The Superior of the In Between – Xemnas.

“With a wielder of the Keyblade roaming the realms, as young as he may be, his heart shall guide him towards the Heartless. When he does, we may finally harness the hearts he releases, and create Kingdom Hearts.”

It was their goal, after all. To unite with the great heart and be granted hearts of their own.

“Shall we approach him, Lord Xemnas?” asked Lexaeus.

There was a moment of silence during which all wondered what would be Xemnas’s answer.

“Interaction with the Keyblade wielder might prove beneficial,” concluded the Superior. “If he sees things from our point of view, then we will gain a valuable ally.”

“And if he doesn’t?” asked Saïx.

A shadow of a smile appeared on Xemnas’s face.

“If he doesn’t then we need not to worry. As a wielder of the Keyblade, the Heartless will be attracted to him, and he will be forced to fight against them. Just as he does now.”

* * *

_The King knew of the outside worlds and the Keyblade, yet that did not seem to favour me at all. Instead, he berated me on interfering in the affairs of other worlds and told me that no darkness could reach the heart of Atlantis. Already there I could notice the falsehood in the king’s words. He knew well that the heart of his world was not safe, but I could not be trusted._

_Many things happened, which I will not record here, but in time the Heart of Atlantis was discovered, sealed underneath the throne room. There was a struggle, and not only was the king fatally wounded, but Kida became bound to the heart of her world. I had not heard of such a symbiosis, but perhaps it was something exclusive to Atlantis. All worlds have their own rules, so who is to say that the shape their heart takes and how it functions is not different?_

_With the king dead and the princess of Atlantis taken captive by the expedition’s mercenaries, I took part in the battle to recover the princess. It was bloody. And flashy too. In the end we won, but Rourke, the commander of the expedition, fell to the darkness, and I had to deal with the Heartless that spawned from him._

_I left that world with the gratitude of its new queen and king, as well as a token of friendship. Although I will treasure it, the crystal Queen Kida gave to me came from the Heart of Atlantis. Perhaps this will give me greater insight on the connections a heart can make to other people, alongside the benefits and the downsides._

_\- Harry’s Report 5_

* * *

Harry blinked.

And then he blinked again.

This was weird. Very weird.

For whatever reason, it seemed he was now a cat. He had experienced changes like these before, when he visited specific worlds with his grandfather, but the change hadn’t been so extreme. Up until now, it had only been a change of clothes.

This was new.

And wicked too.

Harry sat down as best as he could, not used to this form. Looking at his body, it seemed he was a simple black cat, with nothing extra. But then he noticed his tail. Eyes narrowed, a plan began to take shape inside Harry’s mind. Maybe he could…

What followed was a very poor attempt by at catching his own tail, which could have easily earned a human Harry a few bruises considering how many times he just fell with his snout on the dirt-filled ground. The Keyblade wielder soon decided it was a hopeless attempt and stopped.

There were other things he had to do.

There seemed to be some commotion nearby, but Harry wasn’t sure where. He peeked behind the tree where he was, and noticed a small and old stone bridge, underneath which were at least five cats – three kittens and two adult ones. And between him and them were a group of Shadows, slowly getting closer to the felines. The orange one was trying to pounce on the Shadows with his claws out, but was only bounced back by the Heartless, his attack having failed.

Getting out of his hiding spot, Harry ran towards the Heartless, readying himself for not just the battle, but also for what would likely be an awkward conversation afterwards.

* * *

_Everybody wants to be a cat_

_Because a cat's the only cat who knows where it's at_

_Tell me, everybody's pickin' up on that feline beat_

_'Cause everything else is obsolete_

_A square with a horn_

_Makes you wish you weren't born_

_Every time he plays_

_But with a square in the act_

_You can set music back_

_To the caveman days_

\- Harry’s Report 8

* * *

It had been a while since he had come to this place. There was a beauty and serenity to Scala ad Caelum that he could not find in any other world. Perhaps it was because it was because of its buildings, or the fact that it was deserted. Then again, it was there that he spent many good months.

 _“Good times…”_ he thought with a smile.

Harry walked through the corridors of the central citadel of Scala ad Caelum, the sound of his footsteps echoing around him. For some strange reason, no Heartless could enter this world. Perhaps it was an ancient arcane protection cast upon it by ancient Keyblade Masters. Or maybe it was something else entirely. 

There were many rooms here, the majority of which he had never entered, and thus knew nothing about what was inside them. Having spent most of his time in other sections of the citadel, such a thing was expected. There was no need to hide that he wanted to know what exactly was inside them. As they said, curiosity killed the cat, but satisfaction brought it back.

Perhaps it was time to open a door.

* * *

_I travelled to Scala ad Caelum for the first time in some years. It is as I remembered it – a world whose beauty is equalled by its emptiness. Once a seat of power for the wielders of the Keyblade, none are found here anymore. It was here that I was bequeathed the Keyblade, and where my training began as well._

_As I walked the halls of the central citadel, I came upon a room I had never entered before. Inside, I made a fascinating discovery. Covered in dust, I found an abandoned and rather pristine looking Keyblade Armor. I remembered my grandfather mentioning those once or twice, although I don’t remember if he had one of his own._

_When I touched the armour, it somehow became “merged” with my clothing. The cuirass appeared between my shirt and jacket, a gauntlet appeared on my right hand, and my shoes were replaced by the armour’s boots. A flash of light came when I pressed the gauntlet’s top part, and suddenly I was wearing the entire armour. When I did the same, I returned to how I was before._

_Seems I now have a Keyblade Armour of my own. I suppose I should also mention someone I met in Scala ad Caelum, but I’ll leave that for another report._

_\- Harry’s Report 12_

**Notes for the Chapter:**

> Just to clarify, the armour Harry found was the one Xehanort discarded. However, the armour has a few differences when worn by Harry, such as the absence of those huge sleeve-like things on each arm, and the Nobody emblems, as this emblem was apparently designed by Xemnas from his mixed memories of Terra and Xehanort, and thus should not be in the original armour (although they appear in No Heart during the Mirage Arena boss fight).


End file.
